1. Field
Exemplary embodiments of the present invention relate to an image sensor and, more particularly, to a comparator and an analog-to-digital converting system including the same.
The embodiments of the present invention may be applied to various systems such as a single-slope analog-to-digital converter (ADC) and a multi-slope ADC. Thus, the present invention is not limited to the embodiments presented below.
2. Description of the Related Art
An image sensor converts a voltage corresponding to light intensity into a digital code using a comparator and a ramp signal generator. That is, a comparator and a counter, which are included in each column of the image sensor, compare an output voltage of a pixel array with a ramp signal generated from the ramp signal generator. This then generates a code corresponding to an image.
As the gain of the image sensor increases, the slope of the ramp signal generated from the ramp signal generator decreases. Thus, the slope of the output waveform of the comparator also decreases. In this case, the output waveforms of the comparators included in the columns of the image sensor may spread and noise may occur.